cognitive practical

• practical report?

  an experiment to investigate effect that time delay and reconstructive memory has on an eyewitness memory
• aim?

  investigate memory decay and reconstructive memory on an eyewitness recall when participants had a time delay inbetween reporting an incident
• hypothesis?

  alternate: there will be a significant difference in the amount of correctly answered questions (out of 10) in cued recall about a video of a stabbing incident when recall is immediate compared to recall a few weeks later (null= no significant difference)
• sample and evaluation?

  opportunity sample (psychology students available at the time) 16-18 years old, 18 participants 3m 15f at Reigate College.

  • easy and convenient for experimenter to use as its a class that were available at the time to watch the video (but psychology students= demand characteristics)
  • participants are all from reigate so have learned in the same area. difficult to generalise if sample is from 1 area of south england (but participants live in different areas of south england)
• procedure?

  lab experiment using repeated measured design (IV= time between witness of video and recall, DV= memory recall of stabbing, correctly answered Qs out of 10). participants first shown video of an incident and told they'd complete a questionnaire, sitting at individual desk with no distractions. video clip was 2:09 and after instructed to complete fixed response questionnaire (10). after 2 weeks same questionnaire was completed. willcoxon test was completed after
• inferential statistics?

  • looking for difference between scores out of 10 cued response on an incident in a video when asked to recall immediately then delayed by one week
  • ordinal measurement, rank order of scores on 10 cued recall questions about the stabbing incident on video
  • related data, same participants repeated the condition of the questionnaire twice

  willcoxon done
• results?

  calculated value of 16.5 wasn't smaller than the critical value of 13 when N= 11 at a significance level of 5% for a 2 tailed hypothesis. the results aren't significant and the null hypothesis was accepted
• strengths of the study?

  • lab experiment, standardised procedures which give consistent results. the stabbing video was shown to all participants within the same environment and point of view, answering the same 10 fixed responses about the stabbing incident
  • opportunity sample collected, convenient ethical sample present. students in reigate psychology class chosen as a sample
• improvements of weaknesses of study?

  • gen: increase sample size to 16-75 year olds. findings generalise to a wider target population of eyewitnesses
  • validity: try to create a real life situation of crime for eye witnesses. could have 2 people arguing and one person pushes the other, inducing a stressful situation in the environment